There have been known electron beam sterilizers, having various structures, for sterilizing vessels by irradiating the vessels with an electron beam generated from an electron beam irradiation device during the conveyance of the vessels being held by vessel holding means (for example, refer to Patent Document 1 to Patent Document 4).
A sterilizer for sterilizing a vessel with an electron beam disclosed in the above Patent Document 1 is provided with an electron beam generation section, a sterilization processing chamber including an electron beam irradiation window of the electron beam generation section, vessel conveying means for conveying the vessel to be processed in a vertical orientation from an inlet portion of the sterilization processing chamber to an outlet portion thereof, and rotation imparting means for imparting rotation to the vessel during a time at which the vessel has a position just before reaching the electron beam irradiation window of the electron beam generation section to a time at which the vessel has completely passed in front of the irradiation window.
The rotation imparting means is composed of a lateral pair of endless belts disposed to press side surfaces of a neck portion of the vessel from both sides. One of the endless belts has a rotating speed higher than that of the other one of the endless belt, and based on such a difference in the rotating speeds of both the endless belts, the rotation is imparted to the vessel during the conveyance thereof.
An electron beam sterilizer disclosed in the Patent Document 2 includes conveying means having tow wires, by which a mouth portion of the vessel is clamped and the vessel is conveyed in a vertically suspended state, and when the vessel passes an irradiation space of an irradiation chamber, an electron beam irradiating means irradiates the vessel with the electron beam from side surfaces of the vessel. In the electron beam irradiating time, rotating means operates two wires so as to rotate the vessel around a central axis thereof by at least 25 degrees.
An electron beam sterilizer for sterilizing a plastic hollow vessel disclosed in the Patent Document 3 is provided with an orbit (circulation) mechanism for vacuum-sucking and then fixing a bottom portion of a plastic hollow vessel supplied from a supply mechanism and circulating the fixed plastic hollow vessel, and an electron beam irradiation mechanism for irradiating the circulating plastic hollow vessel with the electron beam, and an interval maintaining mechanism capable of maintaining constant an interval between the electron beam irradiation mechanism and the plastic hollow vessel.
A vessel sterilizer disclosed in the Patent Document 4 is provided with a plurality of vessel holding means arranged around a rotary body in a circumferential direction thereof at an equal interval, and each of the vessel holding means has two holding portions so as to hold two vessels side by side in the vertical direction. The rotary body is formed with a conveying path in which an inverting area and a standing conveying area are formed. Inverting means for rotating the vessel holding means around a tangential axial direction as a center of rotation is disposed in the position inverting area, and an electron beam irradiation device is disposed in the standing conveying area.
The vessel held by the vessel holding portion of the vessel holding means is irradiated with the electron beam at the electron beam irradiating position in the standing conveying area, and thereafter, the vessel is inverted in the inverting area in the vertical orientation thereof, at which one surface of the vessel opposite to the surface which has been irradiated with the electron beam is directed to the electron beam irradiation device side. In this orientation, the vessel again receives the electron beam irradiation, thereby completely sterilizing the entire surface of the vessel.    Patent Document 1: Japanese Patent Laid-open Publication No. HEI 11-1212    Patent Document 2: Japanese Patent Laid-open Publication No. HEI 11-19190    Patent Document 3: Japanese Patent Laid-open Publication No. HEI 11-137645    Patent Document 4: Japanese Patent Laid-open Publication No. 2007-29709